ABSTRACT
Angiogenesis is essential for the growth and metastasis of several malignant tumors including colorectal cancer (CRC). The molecular mechanism underlying CRC angiogenesis has not been fully elucidated. Emerging evidence indicates that secreted microRNAs (miRNAs) may mediate the intercellular communication between tumor cells and neighboring endothelial cells to regulate tumor angiogenesis. In addition, exosomes have been shown to carry and deliver miRNAs to regulate angiogenesis. miRNA N-72 is a novel miRNA that plays a regulatory role in the EGF-induced migration of human amnion mesenchymal stem cells. However, the relation between miRNA N-72 and cancer remains unclear. We here found that CRC cells could secrete miRNA N-72. A high miRNA N-72 level was detected in the serum of CRC patients and the cultured CRC cells. Moreover, the CRC cell-secreted miRNA N-72 could promote the migration, tubulogenesis, and permeability of endothelial cells. In addition, the mouse xenograft model was used to verify the facilitating effects of miRNA N-72 on CRC growth, angiogenesis, and metastasis in vivo. Further mechanism analysis revealed that CRC cell-secreted miRNA N-72 could be delivered into endothelial cells via exosomes, which then inhibited cell junctions of endothelial cells by targeting CLDN18 and consequently promoted angiogenesis. Our findings reveal a novel mechanism of CRC angiogenesis and highlight the potential of secreted miRNA N-72 as a therapeutic target and a biomarker for CRC.
ABSTRACT
OBJECTIVE: Metabolic disorders are regarded as hallmarks of multiple myeloma (MM) and are responsible for rapid cancer cell proliferation and tumor growth. However, the exact biological roles of metabolites in MM cells have not been fully explored. This study aimed to explore the feasibility and clinical significance of lactate for MM and investigate the molecular mechanism of lactic acid (Lac) in the proliferation of myeloma cells and cell sensitivity to bortezomib (BTZ). METHODS: Metabolomic analysis of the serum was carried out to obtain metabolites expression and clinical characteristics in MM patients. The CCK8 assay and flow cytometry were used to detect cell proliferation, apoptosis, and cell cycle changes. Western blotting was used to detect the potential mechanism and apoptosis- and cycle-related protein changes. RESULTS: Lactate was highly expressed in both the peripheral blood and bone marrow of MM patients. It was significantly correlated with Durie-Salmon Staging (DS Staging) and the International Staging System (ISS Staging) and the serum and urinary involved/uninvolved free light chain ratios. Patients with relatively high lactate levels had a poor treatment response. Moreover, in vitro experiments showed that Lac could promote the proliferation of tumor cells and decrease the proportion of G0/G1-phase cells, which was accompanied by an increased proportion of S-phase cells. In addition, Lac could decrease tumor sensitivity to BTZ by disrupting the expression of nuclear factor kappa B subunit 2 (NFkB2) and RelB. CONCLUSION: Metabolic changes are important in MM cell proliferation and treatment response; lactate could be used as a biomarker in MM and as a therapeutic target to overcome cell resistance to BTZ.
